To enable full functionality of the SCR-522C/TR1133 radio there are several things 
that you will need to do.  

First you will need to change the <nasal> section of your *set.xml file so that it 
looks like the following.  

<nasal>
   <!-- your other nasal files -->
   <!-- the following three lines must be exactly like what is here -->
   <SCR_522C>
      <file>Aircraft/Instruments-3d/SCR-522C/Nasal/SCR-522C.nas</file>
   </SCR_522C>
</nasal>

This will enable the F12 key to bring up the frequencies dialog. It will also over ride the 
Equipment --> radios menu item so that it brings up the correct menu for the SCR-522C/TR1133
radios.  This also implements other radio features like support for a remote TR switch,  the 
TR switch on the BC-602-A control box,  TR switch lock, channel switching, power switch and 
so on.

For dark conditions when cabin/cockpit illumination is used all of the radio models object 
are illuminated in response to 

<property>/controls/lighting/cabin-norm</property>

If you are using a different property for you cabin/cockpit lights you will need to map your 
lighting property to /controls/lighting/cabin-norm.